When I press the brakes my battery gauge goes down

[bigbigford]

When I press the brakes my battery gauge goes down for just a bit then goes back up after about 30 seconds... The lights also dim at the same time... ... It seems like it only does this when the heat is running on high!

It doesn't do it as bad once it has been running for a while...

Electrical maybe? corrosion on something? Bad battery? I'm not sure where to look.







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[corkey]

lol, as you put your foot on the brake the engine rpm goes down, as it does so does the amount of power coming out of the alternator.
the reason the needle drops is that the fan is drawing a lot of the energy produced, and it takes some time for the power top come back up, have the alternator checked,and check all the wires,

 

[bigbigford]

lol, as you put your foot on the brake the engine rpm goes down, as it does so does the amount of power coming out of the alternator.
the reason the needle drops is that the fan is drawing a lot of the energy produced, and it takes some time for the power top come back up, have the alternator checked,and check all the wires,

haha I know why my rpm goes down.. Im just wondering I see my battery gauge also go down to the Low .. Any suggestions on what wires?

thanks

 

[OneLever]

Sounds like a bad ground wire. When you accelerate force is being put on everything including loose wires. That could be enough to wiggle a loose ground around and cause those issues. When your heat is running on high that puts a large load on the electrical system. So if there is any problem it will show up more readily than if there was a small load on the system.

Check the connections at the brake switch, alternator, and wherever the engine bay ground wires are to start with. You should also include specific vehicle information in your profile in the sidebar. Otherwise no one knows what systems you're talking about.

 

[corkey]

the engine rpm goes down, as it does so does the amount of power coming out of the alternator.

 

[OneLever]

I have never noticed my dash lights or headlights dim from just braking. The alternator does put out less power at lower rpms, but unless you're pushing it the limit load-wise I don't think there should be noticeable dimming. More information would be helpful. I also never notice my dash voltage gauge vary. I suggest he get a multimeter and read the voltage across the battery terminals. Should be around 12.4V after sitting a long time with engine off, and around 14.4V with engine on and idling.